1. Field of the Invention
The present invention relates in general to a liquid crystal display driving circuit for (LCD) and an LCD panel using the same. In particular, the present invention relates to a driving circuit for driving LCD and its light emitting elements.
2. Description of the Related Art
FIG. 1 is a schematic diagram of a conventional liquid crystal display panel (hereinafter, referred to as an “LCD panel”) and the peripheral driving circuits thereof. As shown in the figure, an LCD panel 1 is formed by interlacing data electrodes (represented by D1, D2, D3, . . . , Dm) and gate electrodes (represented by G1, G2, G3, . . . , Gm), each pair of which controls a display cell. As an example, interlacing data electrode D1 and gate electrode G1 control display cell 200. The equivalent circuit of each display cell comprises thin film transistors (TFTs) (Q11-Q1m, Q21-Q2m, . . . , Qn1-Qnm) and storage capacitors (C11-C1m, C21-C2m, . . . , Cn1-Cnm). The gates and drains of these TFTs are respectively connected to gate electrodes (G1-Gn) and data electrodes (D1-Dm). Such a connection can turn on or off all TFTs on the same line (i.e. positioned on the same scan line) using a scan signal of gate electrodes (G1-Gn), thereby controlling the video signals of the data electrodes to be written into the corresponding display cell. It is noted that a display cell only controls the brightness of a single pixel on the LCD panel.
Accordingly, each display cell responds to a single pixel on a monochromatic LCD, but to a single subpixel on a color LCD. The subpixel can be red (represented by “R”), blue (represented by “B”), or green (represented by “G”). In other words, a single pixel is formed by an RGB (three display cells) combination.
In addition, FIG. 1 also shows a part of the driving circuit of the LCD panel 1. The gate driver 10 outputs one or more scan signals (also referred to as scan pulses) to each gate electrode G1, G2, . . . , Gn according to a predetermined sequence. When a scan signal is carried on one gate electrode, the TFTs within all display cells on the same row or scan line are turned on while the TFTs within all display cells on other rows or scan lines may be turned off. When a scan line is selected, data driver 20 outputs a video signal (gray value) to the m display cells of the respective rows through data electrodes D1, D2, . . . , Dm according to the image data to be displayed. After gate driver 10 scans n rows continuously, the display of a single frame is completed. Thus, repeated scans of each scan line can achieve continuous display of an image. As shown in FIG. 1, signal CPV indicates the clock of the gate driver 10, signal CTR indicates the scan control signal received by the gate driver 10, signal LD indicates a data latch signal of the data driver 20, and signal DATA indicates the image signal received by the data driver 20.
In addition, conventional LCD panels include light emitting elements providing illumination to enable display function.
U.S. Pat. No. 5,778,256 discloses a personal digital assistant (PDA) comprising a CPU separate from or incorporated into the microcomputer system of the PDA, a memory separate from or incorporated into the microcomputer system, an LED output, LED driver circuitry coupled between the CPU and the LED output, an interface connector, an interface buffer circuit coupled between the interface connector and the CPU, and an interface data buffer circuit coupled by data lines between the interface connector and the CPU. However, the LED driver circuitry only drives LCDs. Thus, the PDA system requires additional space and assembly for LED driver circuitry. Therefore, the cost of the conventional LCD panels is increased.
Moreover, the LED and LCD driver circuitry of conventional Smartphone also operate independently, suffering the same problems mentioned above.